JP2978554B2 - Lens barrel - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for inserting and bonding a lens component used in a camera or the like into the barrel.

[Conventional technology]

In recent years, when mounting a glass lens on a plastic lens barrel, an arc-shaped lens that comes into contact with the inner peripheral surface of the lens barrel and the part where the outer peripheral surface of the lens is divided into three equal parts to maintain the core accuracy of the lens relative to the lens barrel Attempts have been made to provide a protrusion that forms an inner wall surface and to provide a lens inscribed in the protrusion. In this case, a method for fixing and holding the lens, that is, a method for bonding the lens with an adhesive includes a method shown in FIGS. 7 and 8, and a method for mounting by heat caulking is shown in FIG. There is a method shown in

The former method has a portion to be adhered with the adhesive 11 and a centering portion. When the adhesive 11 is applied, the centering portion (ie, the arc-shaped inner wall surface) is formed. Adhesive 11 also penetrates through and receives lens 12 3
The lens 12 was fixedly held by injecting an adhesive into gaps around the entire periphery of the lens barrel 15 except for the protrusions 14. That is, as shown in FIG. 8, a protrusion 14 having an arc-shaped portion having the same diameter as the outer peripheral surface of the lens 12 and a relief portion 13 having a large diameter are provided respectively. In this configuration, the lens 12 is positioned.

The mounting method by thermal caulking shown in FIG.
The inner peripheral surface of the lens 15 and the outer peripheral surface of the lens 12 are formed to have substantially the same diameter, the lens 12 is inserted into the lens barrel 15, the insertion edge 17 is heated, and the lens 12 is bent in the inner diameter direction. Is fixedly mounted in the lens barrel 15.

[Problems to be solved by the invention]

In the former method of the above conventional mounting method,
To apply the adhesive 11 to the gap between the lens barrel 15 and the lens 12,
When the lens barrel 15 contracts at a low temperature, the lens barrel 15 causes the lens 12 to be distorted because the lens barrel 12 tightens the lens 12. The inner wall surface of the lens barrel 15 and the lens
Since the entire circumference of the outer peripheral surface of 12 is buried with the adhesive 11, there is no air flow at all, so the gas generated when the adhesive 11 is cured fills the inside (between the lenses). The lens 12 was lifted or the lens barrel 15 made of plastic was adversely affected. In addition, the air between the lenses expands and contracts due to the temperature change, causing an obstacle such as moving the lens 12 in the optical axis direction or generating dew inside (between the lenses) due to the temperature change.

Further, in the latter method, that is, in the thermal caulking method, the deflection of the spindle provided in the caulking device, the variation in the mounting of the jig and the lens barrel 15, or the inclination, etc., cause the barrel 15 to be centered with great effort. There was a problem that the lens 12 was out of order. Also, since the abutting portion of the lens barrel 15 against the lens 12 (which is a stop surface in the optical axis direction of the lens 12) is formed on the edge, the edge is crushed by the pressure at the time of caulking and moves in the optical axis direction. However, there was a problem that the position could not be determined. Further, the lens 12 is distorted due to the caulking pressure, and especially at low temperatures, the distortion is further increased, and the optical performance is deteriorated.

The present invention has been made in view of the above problems, and even if a change occurs in the environmental temperature, no distortion occurs in the lens, and
An object of the present invention is to provide a lens barrel capable of reliably holding a lens and stably maintaining optical performance.

[Means and actions for solving the problem]

In order to achieve the above object, the lens barrel of the present invention divides the inner peripheral surface of the lens barrel into at least three equal parts, and the chord whose center of the inscribed circle of the vertex coincides with the optical axis on each division line. A flat surface portion is provided, a lens having the same diameter as the inscribed circle of this flat portion is inserted and arranged, and each flat portion and the lens outer peripheral surface are brought into linear contact in the optical axis direction, and as the distance from the contact portion increases, When the expanding gap is uncured, it has a viscosity that penetrates this contact part when it is not cured, and after curing it is adhered with an elastic adhesive, and between the inner peripheral surface of the lens barrel and the outer peripheral surface of the lens between adjacent flat parts. It is characterized in that a gap portion without an adhesive is provided.

〔Example〕

An embodiment of a lens barrel according to the present invention will be described with reference to the drawings. Note that the same reference numerals are given to the same members and the same configurations in each embodiment, and the description thereof will be made with reference to the first drawing, and the description thereof will be omitted.

First Embodiment FIG. 1 is a front view showing a first embodiment of a lens barrel according to the present invention.

FIG. 2 is an enlarged front view showing a main part of FIG.

 FIG. 3 is a sectional view from the side of FIG.

FIG. 4 is a front view showing a state of a temperature change in FIG.

5 and 6 are front views showing the main part of FIG. 4 in an enlarged manner.

As shown in FIG. 3, an abutment step 3 for positioning the lens 2 to be inserted and mounted in the optical axis direction is provided on the inner peripheral wall surface of one end of the cylindrical lens barrel 1 in accordance with the effective diameter of the lens 2. It has a slightly larger diameter. The inner peripheral wall surface of the lens barrel 1 has a diameter slightly larger than the outer diameter of the lens 2, for example, 0.5 m / m (0.25 m /
m) is formed. Further, on the inner peripheral wall surface of the lens barrel 1, a circumferential surface is divided into three equal parts, and a chord-shaped plane part 4 having a vertex at each of the divided positions is formed long in the optical axis direction. The center of the inscribed circle of the vertex is formed so as to coincide with the optical axis of the lens 2. Further, the diameter of the inscribed circle of the plane portion 4 and the outer diameter of the lens 2 are formed so as to coincide with each other. Therefore, since the flat portion 4 is chord-shaped, the apex of each chord-shaped plane and the outer peripheral surface of the lens 2 come into linear contact in the optical axis direction. As the distance from the contact portion with the outer peripheral surface increases, the gap therebetween increases.

When the lens 2 is inserted into the lens barrel 1, the lens 2
And the inscribed circle of the flat portion 4 is the same, so that it fits with the thick. The dimensional error of the outer diameter and the inscribed circle of the lens 2 is, for example, 0.03 m / m even when the tightened state is reached.
Since the lens barrel 1 is made of plastic, it can easily absorb a dimensional difference of about 0.03 m / m due to deformation due to its elasticity.

Next, the lens 2 comes into contact with the abutting step 3 of the lens barrel 1,
When the lens 2 is disposed at the correct position,
A silicone adhesive 5 having a viscosity of about 200 poise is flowed into and applied from the opening side (lens insertion side) of the lens barrel 1 on both sides of the contact portion. In this case, since the adhesive 5 has a low viscosity, it penetrates deeply from both side surfaces of the flat portion 4 to the bonding surface of the lens 2 in the optical axis direction toward the abutting step portion 3 and is hardened and fixed. .

Therefore, the permeated thin adhesive layer exhibits strong adhesive strength. In particular, it works effectively in the detaching direction of the lens 2 (the direction in which the lens of the lens barrel 1 is inserted).

In addition, the gap between the lens barrel 1 and the lens 2 other than the part where the peripheral surface of each flat part 4 of the lens barrel 1 and the lens 2 is bonded with the adhesive 5 is expanded and contracted due to the temperature change of the lens barrel 1. Is to receive.

That is, when the temperature is low, it contracts inward as shown by the dotted line and arrow in FIGS. 4 and 6, and when it is hot, it expands outward as shown by the dotted line and arrow in FIG. 4 and FIG. When the three bonded portions are evenly contracted and expanded into the branches, the core of the lens 2 does not fluctuate or is distorted due to uneven contraction or expansion.

Further, since the adhesive 5 is made of a material having a high elasticity, it acts as a strong adhesive force at the contact portion of the lens 2 with the lens barrel 1, but at a position distant from the contact portion, that is, the adhesive. In a portion where the layer of the agent 5 is thick, an appropriate elastic force is exerted, and it is configured to adapt to contraction and expansion due to a temperature change of the lens barrel.

In the above-described embodiment, the lens 2 is inserted and disposed only on one side of the lens barrel 1. However, a lens can be inserted and disposed on the other side as well.

Further, in the present embodiment, the adhesive 5 is applied from both sides of the flat portion 4, but the process can be simplified by applying the adhesive 5 from one side and penetrating to the other side by capillary action.

According to the present embodiment having the above configuration, the lens 2 and the lens barrel 1
By providing a space between the lenses 2
Can be prevented from being distorted.

Also, a flat portion is formed at three equally divided positions in the lens barrel 1, and the lens 2 is fitted and inserted into the top of the flat portion 4 so that the adhesive 5 permeates and adheres only to both sides of the flat portion 4. As a result, the core accuracy of the lens 2 due to the temperature change can be secured, and the lens 2 can maintain appropriate strength with respect to the lens barrel 1.
Further, by applying the adhesive 5 only on both sides of the flat portion 4, air permeability in the lens barrel 1 can be secured, so that dew condensation is prevented, the lens 2 is moved by a change in air pressure, or the lens 2 is formed by gas generated during curing. Float prevention and the like can be obtained.

Note that the chord-shaped flat portion 4 is provided in the lens barrel 1 according to the present embodiment.
Can be formed very easily. For example, the outer peripheral surface of the mold insert for molding the inner surface of the lens barrel 1 on the lens assembly side is divided into three equal parts, and the outer peripheral surface of each insert has the inner diameter of the abutting step 3 formed therein. 1, a second shaft forming an insertion portion of the lens 2, and a lens barrel 1.
And a third shaft portion forming an end of the chord-shaped plane portion only by grinding the outer surface of the second shaft portion at the three equally divided positions by flattening the outer surface thereof. 4 can be molded.

〔The invention's effect〕

According to the lens barrel of the present invention described in the embodiment, the outer peripheral surface of the lens is joined to a flat portion provided by dividing the inner peripheral surface of the lens barrel into at least three equal parts, and both are linearly contacted in the optical axis direction. In addition to the lens being held in this state, it is bonded and held at this contact point, preventing distortion of the lens due to temperature changes between the lens and the lens barrel, preventing the lens core from being out of alignment, and ensuring proper holding strength of the lens. Can be

In addition, since a gap is provided between the inner peripheral surface of the lens barrel and the outer peripheral surface of the lens, where no adhesive is present, air permeability with the outside is secured, so that dew condensation on the lens surface is prevented, or movement of the lens due to pressure change. This has excellent effects in terms of quality, such as prevention of the occurrence of air bubbles and floating due to gas generated when the adhesive is cured.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of a lens barrel according to the present invention. FIG. 2 is an enlarged front view showing a main part of FIG. 1; FIG. 3 is a sectional view from the side of FIG. FIG. 4 is a front view showing a state of a temperature change in FIG. FIG. 5 and FIG. 6 are front views showing the main part of FIG. 4 in an enlarged manner. 7 and 8 are a sectional view from the side and a sectional view from the front of the conventional lens barrel. FIG. 9 is a sectional view from the side of another conventional lens barrel. DESCRIPTION OF SYMBOLS 1 ... Barrel 2 ... Lens 3 ... Step part 4 ... Flat part (chordal flat part) 5 ... Adhesive

Claims (1)

(57) [Claims] 1. An inner peripheral surface of a lens barrel is divided into at least three equal parts, and a chord-like flat part whose center of an inscribed circle of a vertex coincides with an optical axis is provided on each of the dividing lines. A lens having the same diameter as the inscribed circle is inserted and arranged so that each flat portion and the outer peripheral surface of the lens come into linear contact with each other in the optical axis direction. Adhesive with an adhesive that has a penetrating viscosity and is hardened after hardening, and a gap without adhesive is provided between the inner peripheral surface of the lens barrel and the outer peripheral surface of the lens between adjacent flat portions. A lens barrel characterized by the following.